Alphabetic Index FY2027

M18

Osteoarthritis of first carpometacarpal joint

FY2027Chapter 13: Diseases of the musculoskeletal system and connective tissue/M15–M19 Osteoarthritis

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

M18 is a non-billable ICD-10-CM code category for osteoarthritis of first carpometacarpal joint. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are M18.0 Bilateral primary osteoarthritis of first carpometacarpal joints, M18.1 Unilateral primary osteoarthritis of first carpometacarpal joint, M18.2 Bilateral post-traumatic osteoarthritis of first carpometacarpal joints, M18.3 Unilateral post-traumatic osteoarthritis of first carpometacarpal joint and 3 more. Its coding notes include 11 Excludes2 entries.

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (11 notes)
Inherited from M15–M19 Osteoarthritis
  • osteoarthritis of spine (M47.-)
Inherited from Chapter 13 Diseases of the musculoskeletal system and connective tissue
  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Notes

Also from chapter/block level (1 note)
Inherited from Chapter 13 Diseases of the musculoskeletal system and connective tissue
  • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

More specific codes under M18 7